Radio direction finder



April 24, 1934. F. woons 1,956,369

RADIO DIRECTION FINDER Filed July 12, 1930 2 Sheets-Sheet 1' INVENTOR FRED WOODS ATTORNEY A ril 24, 1934. F. WOODS 1,956,369

RADIO DIRECTION FINDER Filed July 12, 1930 2 Sheets-Sheet 2 I I I 4 7 4 I V/////////////////I////////// Malay/11101111100 INVENTOR FRED WOODS ATTORNEY Patented Apr. 24, 1934 PATENT OFFICE RADIO DIRECTION FINDER Fred Woods, Richmond, England, assignor to Radio Corporation of America, a corporation of Delaware Application July 12, 1930, Serial No. 467,433 In Great Britain August 23, 1929 2 Claims.

This invention relates to radio direction finders, and has forits object to provide an improved radio direction finding installation suitable for use on shipboard and similarlocations.

When direction finding aerials of the rotating coil type are installed, their actual location is frequently determined by considerations of manipulating convenience with the result that the site chosen is often by no means the best from m the radio point of view. This disadvantage is often most serious in shipboard installations, and directional finding aerials are commonly located in positions in which electrical obstruction exists and/or near to recording and receiving instru-- ments and amplifiers which may give rise to inductive interference.

According to this invention a radio direction finding installation, suitable for use on shipboard, comprises a rotatable direction finding 20 frame aerial adapted to be remotely controlled by means of a hydraulic motor or motors operated by liquid transmitted thereto from a distance.

Preferably the motor or motors, comprise each a fixed piston and a moving cylinder, the latter carrying or being formed with a rack co-operating with a pinion which rotates the aerial.

The invention is illustrated in the accompanying drawings.

In the drawings Figure 1 is a schematic plan showing one arrangement in accordance with the invention with the covers removed.

Figure 2 is an end elevation of Figure 1, the transmitted device being shown in section on the line X-X of Figure 1.

Figure 3 is a section of the motor device taken on the line Z-Z of Figure 2; while Figure 4 is a schematic plan of a modified construction.

Referring to the drawings the shaft 1 of a rotatable frame aerial 2 carries a pinion 3 engaging a rack 4 formed in the side of, and longitudinal to a cylindrical member 5 which is open at each end but has a partition 6 in the middle so that in effect the said member constitutes two cylinders placed back to back in the same straight line. Fixed pistons '7, '7 are located in each cylinder, said pistons being mounted on fixed connecting rods, 8, 8, carried in a suitable frame 9. The piston heads are separated by a distance substantially equal to the working length of one cylinder, and both pistons and rods are bored at 10 to admit liquid to the cylinders. Suitable connecting pipes 11 of any desired length are attached at the ends of the liquid admission borings, said pipes extending to the remote control station where they are attached at the ends of the borings of a piece of apparatus which is precisely similar to the two cylinder hydraulic motor above described except that the frame aerial is replaced by a control handle 12 moving over a scale 13.

In the drawings parts in the controlling or transmitter apparatus corresponding to parts in the above described motor are indicated by like reference numerals primed. The driving and driven motors are set in corresponding positions, and the complete hydraulic circuit filled with oil or other suitable liquid. It will be seen that with this arrangement, if the control handle 12 be moved, the cylindrical member 5 geared thereto is moved longitudinally so that the partition 6 between the cylinders proper approaches one piston head and recedes from the other. In consequence, liquid is forced out of one cylinder and through a connecting pipe 11 into one cylinder of the driven motor, thus compelling the cylindrical member 5 thereof to move a distance corresponding to the movement of the cylindrical member 5' in the driving motor, and to displace liquidround the other half of the hydraulic circuit.

Obviously it is not necessary that the driving and driven motors be of the same size though this will generally be found the most convenient arrangement. If desired, they may be of different sizes, and the disparity of liquid displacement per unit length of stroke between the two motors made up by giving them different lengths of stroke, and, of course, choosing different gear ratios for the rack and pinion drives, so that the aerial accurately follows up the control handle.

The employment of fixed pistons and moving cylinders leads to a very simple construction and renders the provision of glands, cup leathers or 5 stuffing boxes unnecessary to ensure fluid tightness. In order, however, to make quite certain that there shall be no air ingress, it is preferred toenclose both the driving and driven motors each in a container not shown filled with the Working fluid.

Alternatively as shown in Figure 4 a parallel branch pipe 14 may be provided connecting the two connecting pipes 11 together, said branch pipe being provided with a T piece 15 in fluid 5 connection with a cylinder 16 containing a piston 17 upon which pressure is maintained by a weight 18 or by a spring. The former method of preventing air ingress is, however, to be preferred in most cases.

The present invention enables a rotating directional aerial to be installed in the most desirable position, substantially without regard to consideration of manipulating convenience. For shipboard installation, it is preferred generally to install the aerial on the amidships line about 3 feet or more above the standard compass. The aerial may be conveniently supposed by a rectangular or bridge-like structure of brass tubes, preferably telescopic, so that the frame elevation can be adjusted at will. The uprights may form part of the guard rails normally fitted in such a position, whilst the tubular supports may be utilized as conduits for conductors and so forth.

The hydraulic motors employed may be quite small; in fact, a construction in which each is enclosed in a fluid containing box about 10 by 4 has been found quite satisfactory.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:-

1. A radio direction finder comprising a rotatable loop aerial, hydraulic means for rotating said loop aerial, said hydraulic means comprising a fluid motor with fixed pistons, and a gear rack fixed to a movable cylinder which is geared to a manual control, fluid connection means from said fluid motor to a second fiuid motor with fixed pistons, and a gear rack fixed to a movable cylinder which is geared to said rotatable aerial so that when a change is made in the manual control a corresponding change will be made in the loop aerial.

2. A radio direction finder comprising a rotatable loop aerial, a hydraulic control system for rotating said loop aerial, said hydraulic control system comprising a fluid motor with fixed pis- 

